Conventionally, for example, a train slide control device described in Patent Document 1 is configured such that a velocity sensor detects the number of revolutions of each wheel, and when a difference is generated between the number of revolutions of one wheel and the number of revolutions of other wheels while a brake is operated, compressed air supplied to a brake cylinder of a sliding wheel is exhausted or supplied to increase or decrease a brake cylinder pressure for preventing a slide. The brake cylinder pressure is provided by amplifying compressed air outputted according to opening and closing operations of electromagnetic valves for regular use brake control and slide control (hereinafter, “electromagnetic valve unit”) by a relay valve.    Patent Document 1: Japanese Patent Application Laid-open No. 2004-306865